A baby diagnosed with liver disease can't be cured with medicine, doctors say. Without a new organ, most infants with problem livers will die. Doctors facing a severe shortage of transplants for children began experimenting with living donors. Surgeons take a piece of liver from a healthy person and implant it in a sick baby. The baby's new liver grows with the child; the donor's liver regenerates. Eight years after the first procedure was performed in Brazil, doctors say the living-donor procedure is proving successful about 90% of the time.

E. Donnall Thomas, a physician who pioneered the use of bone marrow transplants in leukemia patients and won the 1990 Nobel Prize in medicine, died Saturday in Seattle of heart disease. He was 92. The Fred Hutchinson Cancer Research Center in Seattle, which Thomas joined in 1974, announced his death. Thomas' work is among the greatest success stories in the treatment of cancer. Bone marrow transplantation and its sister therapy, blood stem cell transplantation, have improved the survival rates for patients with some blood cancers to around 90% from almost zero.

The most important garden chore during this often sweltering month is watering, even for drought-tolerant plants. Make sure that plants are getting enough water by regularly checking soil moisture with your finger or a moisture meter. Planting during hot, dry weather is possible, as long as you water delicate transplants and seeds well and keep transplants shaded for a few days. Most summer vegetable transplants planted this month will mature in fall.

Transplants of tissue from human fetuses offer hope in treating AIDS and other diseases, but doctors acknowledge the need to resolve ethical questions surrounding the practice. Anti-abortionists have denounced procedures involving the use of tissue from fetuses obtained through spontaneous or induced abortions. The transplants, mostly of brain and glandular tissue, are supported by the American Medical Assn.'s Council on Scientific Affairs and its Council on Ethical and Judicial Affairs.

Older corneas seem to transplant as well as younger ones, says a major new study that promises to expand the age of cornea donation from 65 to 75. Cincinnati researchers randomly assigned cornea recipients to get either younger or older tissue and found the corneas of both groups survived just as well five years later, they reported Tuesday in the journal Ophthalmology. The cornea is the clear covering for the front of the eye, crucial for helping it focus light. More than 39,000 corneal transplants were performed last year, according to the Eye Bank Assn.

Re "Spared as children -- then cut loose," April 13 The sense of entitlement that Ana Puente has is what angers and frustrates many Americans about illegal immigrants. Her statement, "They should take care of me at UCLA for the rest of my life because I've been there since I was a baby," left me speechless. What has Puente contributed to American society in her time here? What has she done to deserve to be treated for free for the rest of her life in this country? I am paying more for my daughter's retainer than Puente is paying for a lifetime of liver transplants and follow-up care.

An American doctor treating victims of the Chernobyl disaster said today that more of them will die because they received lethal doses of radiation released by the nuclear power plant. Dr. Robert P. Gale, a UCLA bone marrow expert, told a packed news conference that Soviet and foreign specialists have identified 35 people who suffered severe radiation exposure after the April 26 accident at the Ukrainian plant.

The first trial in a handful of humans has suggested that injecting patients with Type 1 diabetes with an inexpensive vaccine normally used to prevent tuberculosis can block destruction of insulin-secreting pancreatic cells in humans and allow regeneration of the pancreas. Such a finding, if confirmed and expanded on, could lay the foundation for freeing the estimated 1 million U.S. Type 1 diabetics from their daily insulin shots. It brings up a word that is rarely or never used in considering the disease: "cure.

The microorganisms in the human gut appear to play a pivotal role in determining whether a person is lean or obese, new research shows. The study, published online Thursday by the journal Science, is the strongest evidence yet that what's inside an individual's digestive tract influences the risk of obesity and its related health problems, such as Type 2 diabetes. The work helps explain the nation's 30-year run-up in excess weight - and it may supply a potential solution to the resulting epidemic, experts said.